The present invention relates to a novel fluoro-carbon resinous laminate and a method of producing said laminate. More particularly, the invention relates to a fluoro-carbon resinous laminate comprising a plastic film having single surface or both surfaces coated with fluoro-carbon resinous layers and a method of producing said fluoro-carbon resinous laminate.
Conventional fluoro-carbon resinous laminate comprising layers of fluoro-carbon resin laminated on single surface or both surfaces of a plastic film is mainly wound on a conductor such as copper in taped form and used for motor coils, cables, or electric wires in an aircraft. There are a variety of laminates according to combination of plastic films and fluoro-carbon resinous layers having a variety of thickness. For example, such a laminate comprising a 25 .mu.m thick plastic film having layers of fluoro-carbon resin having 2.5 .mu.m through 25 .mu.m thickness laminated on single surface or both surfaces thereof has mainly been used.
Normally, such a conventional fluoro-carbon resinous laminate comprising a plastic film having single surface or both surfaces laminated with fluoro-carbon resinous layer has been produced via a method of producing fluoro-carbon resinous laminate by laminating a fluoro-carbon resinous film (sheet) with a plastic film or a method comprising a step of coating a plastic film with fluoro-carbon resinous dispersion (coating solution), a step of drying it, and thereafter a step of hardening via curing the dried resinous layers.
In the case of producing fluoro-carbon resinous laminate having a thickness of less than 10 .mu.m, for example, having 2.5 .mu.m of thickness, normally, the method of coating a plastic film with fluoro-carbon resinous dispersion (coating solution) has been used.
However, when executing the above coating method, it is necessary to devise the coating method to entail production process technical difficulty.
Moreover, even though coating process became practicable via a devised art, there was still a critical problem to be solved in that noticeable cracks were generated on the surface of fluoro-carbon resinous layers. This symptom was quite noticeable whenever laminating thick fluoro-carbon resinous layers such as the one having a minimum of 10 .mu.m of thickness for example.
Moreover, in the case of thermally sealing taped laminate containing cracks after winding it onto a conductor, cracks cause void to be generated to easily lead to generation of electrical discharge to raise a problem in terms of electrical insulation characteristic.
Due to the above problem, it is proved in general that fluoro-carbon resinous laminate produced by the lamination of fluoro-carbon resinous film generates better quality than the one generated by applying the coating method.
Nevertheless, in the case of producing fluoro-carbon resinous laminate by applying the lamination method, since fluoro-carbon resinous film costs higher than dispersion, and yet, due to complicated steps taken to prevent cracks from being generated during lamination process, the lamination method has such a problem as to entail higher production cost than the coating method.
Thus, in order to solve the above problems and provide a novel fluoro-carbon resinous laminate and a method of producing said laminate produced by coating single surface or both surfaces of a plastic film with fluoro-carbon resinous dispersion without raising a problem on appearance, inventors have strenuously followed up studies and experiments and eventually achieved the present invention.